Modified entity classes. Added ASP.NET Identity 2.0 entities.
Added a contruct initializing collection types, new properties, reworked class xml comment.
Revert "Added a contruct initializing collection types, new properties, reworked class xml comment."

This reverts commit a1a930680b79cc7f482bdc38055b7c4a0af8c3b9.
Modified properties of Category, Post and Topic classes.
Cleaned up entity classes and made some very minor fixes.
Minor entity fixes.
Move countries xml file to _Common physical folder.
Changed properties names in Group, User and Category class to look nicer and make more sense overally.
Added configuration logic to CategoryConfiguration.
Configured properties across Group, Message, Post and User classes. Configured Messages, CategoryGroups Groups.
Added a configuration for Ban Entity.
Added logic to User, Post configuration and added RawContent property to Message, Post and PostEdit classes.